Chronic kidney disease (CKD) is diagnosed by having an estimated glomerular filtration rate (eGFR) of less than 60 milliliters per minute per 1.73 meters squared and this need to be present for at least 3 months. CKD can also be diagnosed with evidence of blood, protein or infection in the urine for greater than 3 months. Your eGFR is just barely below the normal range. I suggest that you have testing performed to confirm this level in 2 or 3 months. At times we see transient decreases in kidney function that is reversible. I also suggest that you have urine testing looking for evidence of CKD. Since you have stone disease, you may have CKD on that basis as well as your diabetes. The oncocytoma should not cause evidence of CKD or abnormalities in the urine.